The password expiration information for a user is contained in the last 6 fields. Password expiration for a select user can be disabled by editing the /etc/shadow file

You can also use chage command. The chage command changes the number of days between password changes and the date of the last password change. This information is used by the system to determine when a user must change his/her password.

Last password change : May 12, 2008Password expires : neverPassword inactive : neverAccount expires : neverMinimum number of days between password change : 0Maximum number of days between password change : 99999Number of days of warning before password expires : 7

To disable password aging / expiration for user foo, type command as follows and set:Minimum Password Age to 0Maximum Password Age to 99999Password Inactive to -1Account Expiration Date to -1